Cryptosporidium is a leading cause of childhood diarrhea in developing countries. We investigated symptomatic and asymptomatic cryptosporidiosis in 20 children less than two years of age in a semi-urban slum in southern India. All surveillance (conducted every two weeks) and diarrheal samples from 20 children (n = 1,036) with cryptosporidial diarrhea previously identified by stool microscopy were tested by polymerase chain reaction–restriction fragment length polymorphism for species and subgenotype determination. Thirty-five episodes of cryptosporidiosis were identified in 20 children, of which 25 were diarrheal. Fifteen episodes were associated with prolonged oocyst shedding. Multiple episodes of cryptosporidiosis occurred in 40% of the children. Most infections were with C. hominis, subtype Ia. Children with multiple infections had significantly lower weight-for-age and height-for-age Z scores at 24 months but had scores comparable with children with a single episode by 36 months. Multiple symptomatic Cryptosporidium infections associated with prolonged oocyst shedding occur frequently in this disease-endemic area and may contribute to the long-term effects of cryptosporidiosis on physical growth in these children.

Noroviruses are an important cause of gastroenteritis but little is known about disease and re-infection rates in community settings in Asia. Disease, re-infection rates, strain prevalence and genetic susceptibility to noroviruses were investigated in a birth cohort of 373 Indian children followed up for three years. Stool samples from 1856 diarrheal episodes and 147 vomiting only episodes were screened for norovirus by RT-PCR. Norovirus positivity was correlated with clinical data, secretor status and ABO blood group. Of 1856 diarrheal episodes, 207 (11.2%) were associated with norovirus, of which 49(2.6%) were norovirus GI, 150(8.1%) norovirus GII, and 8 (0.4%) were mixed infections with both norovirus GI and GII. Of the 147 vomiting only episodes, 30 (20.4%) were positive for norovirus in stool, of which 7 (4.8%) were norovirus GI and 23 (15.6%) GII. At least a third of the children developed norovirus associated diarrhea, with the first episode at a median age of 5 and 8 months for norovirus GI and GII, respectively. Norovirus GI.3 and GII.4 were the predominant genotypes (40.3% and 53.0%) with strain diversity and change in the predominant sub-cluster over time observed among GII viruses. A second episode of norovirus gastroenteritis was documented in 44/174 (25.3%) ever-infected children. Children with the G428A homozygous mutation for inactivation of the FUT2 enzyme (se⁴²⁸se⁴²⁸) were at a significantly lower risk (48/190) of infection with norovirus (p = 0.01). This is the first report of norovirus documenting disease, re-infection and genetic susceptibility in an Asian birth cohort. The high incidence and apparent lack of genogroupII specific immunity indicate the need for careful studies on further characterization of strains, asymptomatic infection and shedding and immune response to further our understanding of norovirus infection and disease.

Importance: Vaccine breakthrough by an emergent SARS-CoV-2 variant poses a great risk to global public health. Objective: To determine the SARS-CoV-2 variant responsible for 6 cases of vaccine breakthrough. Design: Nasopharyngeal swabs from suspected vaccine breakthrough cases were tested for SARS-CoV-2 by qPCR for Wuhan-Hu1 and Alpha variant. Positive samples were then sequenced by Swift Normalase Amplicon Panels to determine the causal variant. Setting: Transmission event occurred at events surrounding a wedding outside of Houston, TX. Two patients from India, likely transmitted the Delta variant to other guests. Participants: Following a positive SARS-CoV-2 qPCR test at a third-party site, six fully vaccinated patients were investigated. Three males and three females ranged from 53 to 69 years old. One patient suffered from diabetes while three others were classified as overweight. No significant other comorbidities were identified. None of the patients had a history of failed vaccination. Key Points: Question: Which SARS-CoV-2 variant is responsible for 6 cases of vaccine breakthrough, one interventional monoclonal antibody treatment, and one death? Findings: Viral sequencing revealed 6 vaccinated patients were infected with the Delta SARS-CoV-2 variant. With no histories of vaccine breakthrough, this suggests Delta variant may possess immune evasion in patients that received the Pfizer BNT162b2, Moderna mRNA-1273, and Covaxin BBV152. Meaning: Delta variant may pose the highest risk out of any currently circulating SARS-CoV-2 variants, with increased transmissibility over Alpha variant and possible vaccine breakthrough.

Background. Rotavirus gastroenteritis results in significant morbidity and mortality in Indian children. Although there are numerous studies on rotavirus diarrhea, there are few reports on antigenemia and extraintestinal presentations in these populations.